---
redirect_from:
  - /config/databases/mysql
---

# MySQL

## Prerequisites

- The hostname for the [MySQL][mysql] database server
- The username/password for the [MySQL][mysql] database server
- The name of the database to use within the [MySQL][mysql] database server

## Setup

### Manual

Add the following to a `.env` file in your Cube project:

```dotenv
CUBEJS_DB_TYPE=mysql
CUBEJS_DB_HOST=my.mysql.host
CUBEJS_DB_NAME=my_mysql_database
CUBEJS_DB_USER=mysql_user
CUBEJS_DB_PASS=**********
```

## Environment Variables

| Environment Variable    | Description                                                                         | Possible Values           | Required |
| ----------------------- | ----------------------------------------------------------------------------------- | ------------------------- | :------: |
| `CUBEJS_DB_HOST`        | The host URL for a database                                                         | A valid database host URL |    ✅    |
| `CUBEJS_DB_SOCKET_PATH` | See [connecting via a Unix socket](#connecting-via-a-unix-socket)                   | A valid path to a socket  |    ❌    |
| `CUBEJS_DB_PORT`        | The port for the database connection                                                | A valid port number       |    ❌    |
| `CUBEJS_DB_NAME`        | The name of the database to connect to                                              | A valid database name     |    ✅    |
| `CUBEJS_DB_USER`        | The username used to connect to the database                                        | A valid database username |    ✅    |
| `CUBEJS_DB_PASS`        | The password used to connect to the database                                        | A valid database password |    ✅    |
| `CUBEJS_DB_SSL`         | If `true`, enables SSL encryption for database connections from Cube                | `true`, `false`           |    ❌    |
| `CUBEJS_CONCURRENCY`    | The number of concurrent connections each queue has to the database. Default is `2` | A valid number            |    ❌    |
| `CUBEJS_DB_MAX_POOL`    | The maximum number of concurrent database connections to pool. Default is `8`       | A valid number            |    ❌    |

## Pre-Aggregation Feature Support

### count_distinct_approx

Measures of type
[`count_distinct_approx`][ref-schema-ref-types-formats-countdistinctapprox] can
not be used in pre-aggregations when using MySQL as a source database.

## Pre-Aggregation Build Strategies

<InfoBox>

To learn more about pre-aggregation build strategies, [head
here][ref-caching-using-preaggs-build-strats].

</InfoBox>

| Feature       | Works with read-only mode? | Is default? |
| ------------- | :------------------------: | :---------: |
| Batching      |             ✅             |     ✅      |
| Export Bucket |             -              |      -      |

By default, MySQL uses [batching][self-preaggs-batching] to build
pre-aggregations.

### Batching

No extra configuration is required to configure batching for MySQL.

### Export Bucket

MySQL does not support export buckets.

## SSL

To enable SSL-encrypted connections between Cube and MySQL, set the
`CUBEJS_DB_SSL` environment variable to `true`. For more information on how to
configure custom certificates, please check out [Enable SSL Connections to the
Database][ref-recipe-enable-ssl].

## Additional configuration

### Connecting via a Unix socket

To connect to a local MySQL database using a Unix socket, use the
`CUBEJS_DB_SOCKET_PATH` environment variable, for example:

```dotenv
CUBEJS_DB_SOCKET_PATH=/var/run/mysqld/mysqld.sock
```

When doing so, `CUBEJS_DB_HOST` will be ignored.

### Connecting to MySQL 8

MySQL 8 uses a new default authentication plugin (`caching_sha2_password`)
whereas previous version used `mysql_native_password`. Please
[see this answer on StackOverflow](https://stackoverflow.com/a/50377944)
for a workaround.

<InfoBox>

For additional details, check the [relevant issue](https://github.com/cube-js/cube/issues/3525) on GitHub.

</InfoBox>

[mysql]: https://www.mysql.com/
[ref-caching-using-preaggs-build-strats]:
  /product/caching/using-pre-aggregations#pre-aggregation-build-strategies
[ref-recipe-enable-ssl]:
  /guides/recipes/data-sources/using-ssl-connections-to-data-source
[ref-schema-ref-types-formats-countdistinctapprox]: /reference/data-model/types-and-formats#count_distinct_approx
[self-preaggs-batching]: #batching
[self-ssl]: #ssl
